The series (those I have read thus far) is replete with references to various mythological tales from around the world. Whether it is Greek myths/legends or drawing from the faith of Islam, Herbert incorporates the common allusions and themes which are inherent in many of the world's belief systems.
One is particularly struck by the similarities of the Fish Speakers to the Bacchae of Dionysus in Euripides play. This similarity becomes readily apparent in the chapter where Duncan Idaho attends the Great Sharing:
"Do you know who they lampoon at the Feast, Duncan?"Idaho is one of the few men who attends the Great Sharing between the Fish Speakers and their God. In ancient Greece, Cadmus and Teiresias are the only men who dance with the Bacchae:
"Men who have offended them. Listen to them when they talk softly among themselves."
Cadmus: "Are we the only men who will dance for Bacchus?"Duncan Idaho is also exposed to the latent power in the Fish Speakers:
Teiresias: "They are all blind. Only we can see."
"One word from Leto and these women would tear an offender to pieces. They would not question. They would act."This unquestioning act indeed occurs in Euripides' drama, wherein the hapless Pentheus is torn apart by his own female relatives, while they were possessed by the madness of their god, Dionysus:
"In vain he cries to his aunts to protect him from his mother. Autonoe seized one arm, Ino the other, and between them he was torn to pieces, while his mother shouted, 'Victory! Victory! we have done it; the glory is ours!'"(Bulfinch's Mythology)If you are not familiar with Greek mythology, the Bacchae are the female devotees of the Greek god of wine, Dionysus. However, Dionysus was a foreign god. He represented chaos and the Other. He intoxicates his followers, driving them to madness and orgiastic fury. This presented a challenge to traditional Greek customs and beliefs, much in the way the God Emperor presents a challenge to the old order of the empire: the Bene Gesserit, the Guild, etc.
This incorporation of myth into the framework of the story is one of the things which has always captivated me about Herbert's Dune series. It is never overly blatant; like the Fish Speakers, it sometimes lies just beneath the surface. Definitely keep a copy of Bulfinch's Mythology or Mythology by Edith Hamilton close at hand, whether you're familiar with mythology or not. I'm certainly looking forward to reading Heretics of Dune and Chapterhouse Dune to complete the series.